Advances in photovoltaic technology, which is used to make solar panels, have helped solar energy gain mass appeal among those wishing to reduce their carbon footprint and decrease their monthly energy costs. In the past decade, the number of residential homes equipped with solar panels has grown significantly. However, conventional rooftop solar panels often leave some portion of the roof uncovered, thus missing the opportunity to collect as much solar energy as possible. In addition, these conventional rooftop panels can be industrial-looking and often lack the curb appeal many homeowners desire.
Solar shingles or tiles, on the other hand, are solar modules that have a similar appearance to conventional roof shingles or tiles. In addition to converting sunlight into electricity, the solar shingles or tiles also protect the roof from weather the same way traditional shingles or tiles do. They allow homeowners to turn their roof into an electricity generator while maintaining a conventional roofline.
Compared to traditional solar panels that were placed inside an aluminum frame, solar roof tiles are often frameless. This means that moisture may permeate the encapsulant from the edges of the tiles under wet conditions. On the other hand, many high-efficiency Si heterojunction (SHJ) solar cells use transparent conductive oxide (TCO) (e.g., indium tin oxide (ITO) or zinc oxide (ZnO)) for electrical contact. Compared to diffusion-based solar cells, TCO-based SHJ solar cells are more susceptible to moisture ingress. More specifically, conventional TCO materials tend to lose their material properties when exposed to moisture and may even serve as a medium through which moisture can reach the junction of the solar cell, thus degrading the solar cell performance drastically. Photovoltaic structures encapsulated within the solar roof tiles need to be moisture resistant.